Internal combustion engines have long employed air flow conduits to provide vacuum assist for automobile subsystems, such as brakes; automatic transmissions and others. These systems often employed check valves located along the air flow conduit to prevent subsystem back pressure from reaching the engine, a typical check valve of this sort is described in U.S. Pat. No. 3,889,710.
These designs were improved upon with a check valve of the type disclosed in U.S. Pat. No. 5,291,916, which provided for a space-saving vacuum booster check valve located along a conduit between the air intake manifold and the brake booster. The check valve included three or more ports connected by hoses to the air intake, block, and one or more vehicle subsystems. Venturi tubes in the valve body connected the various ports to provide a vacuum booster effect to the subsystem. A common concave valve seat and diaphragm served to prevent back pressure from the subsystem from entering the main conduit between the air intake and the engine block.
While such designs work well, modern engine specifications often demand higher boosted vacuum flow and quicker vacuum recovery from the vacuum booster subsystems. The present invention is directed toward meeting these needs.